Title metadata

From DSiBrew

Title metadata, or TMD for short, is a format used to store information about a title (DSiWare, etc.) and all its installed contents, including which contents they consist of and their SHA1 hashes. The format between Wii and DSi Title metadata appears to be identical.

Many operations are done in terms of 64-byte blocks, which means you will often see padding out to the nearest 64-byte boundary at the end of a field.